By Andrew Lycett. Overlook. 434 pp. $35 In 1933, a prodigiously gifted teenage poet left the provincial Welsh town of Swansea and came up to London to brave the treacherous waters of the literary world. The older, aristocratic Bloomsbury crowd still dominated the scene, together with a younger, rising group of left-leaning Cambridge- and Oxford-educated poets. Dylan Thomas, the son of a remote, alcoholic schoolmaster father and a naive, overprotective mother, had grown up in a household under perpetual financial stress and had gone to work for a Swansea newspaper rather than to a university. By the age of 18, he had already written some of the stunning lyric poetry that within a few years would make him famous -- work that did not fit conveniently into any of the current fashionable movements. At 19 he met the fragile, possessive and immensely seductive Caitlin Macnamara, whom he soon rashly married. It was a tormented union of two needy childlike artists, unable to either separate or provide emotional sustenance for each other -- or even the most basic household comforts for themselves and their children.

With little visible means of support for most of his career, Thomas made his unsteady way in the world with the aid of a beautiful voice, the face of a mischievous cherub, a headful of red-gold pre-Raphaelite curls, a talent for self-promotion that masked considerable insecurity, an instinct for how to get taken up by romantically inclined older women and wealthy patrons. But he also had a raging thirst for alcohol that would prove fatal 20 years down the road, when he was at the height of his fame but had essentially ceased writing poetry. His trajectory was that of a shooting star -- a great burst of light in the literary firmament followed by a swift, cataclysmic flameout.

Since Chatterton and Shelley, the figure of the poete maudit has had an irresistible allure, not only for the public but for the biographer. For the latter, there is, of course, the promise of good copy; thus the proliferating works about such emblematically self-destructive writers as Jack Kerouac and Sylvia Plath. Given Thomas's enduring popularity and his riveting declaration, "I hold a beast, an angel and a madman in me," it is surprising that Andrew Lycett's biography is the first new one to appear in more than a decade.

Thomas drank himself to death, expiring in a Greenwich Village hospital far from home in 1953. It was an era when, believe it or not, literature was still big news, when a charismatic poet like Thomas could fill large halls across America and be mobbed by voraciously enthusiastic fans. Though Kerouac and Allen Ginsberg largely replaced him in the public's imagination, Thomas remained a powerful legend. For years his aura lingered in the dingy corridors of the Chelsea Hotel and in the smoky gloom of the White Horse Tavern, his favorite watering hole during his three tumultuous visits to our country.

Like other angel/madmen, Thomas left a lengthy trail of anecdote and gossip behind him -- exactly the kind of material that makes the task of writing a lively biography look deceptively easy. In Thomas's case, the London literary world of the 1930s and 1940s -- full of scandal, vicious infighting, drunken brawls and sexual couplings of all descriptions -- also provides the biographer with more color and shock value than one can find in any issue of Vanity Fair. But in truth, artists like Thomas are extremely challenging subjects, mercurial by nature, full of inconsistencies, riddles even to themselves.

"Dylan had a clear mission," Lycett writes. "He recognized the conflicting sides to his personality and sought to reconcile them through poetry." ("My enquiry is as to their working," Thomas wrote of the opposing forces within himself, "and my problem is their subjugation and victory, downthrow and upheaval.") Unfortunately, Lycett, a journalist by trade and the eclectic author of biographies of Moammar Gaddafi, Ian Fleming and Rudyard Kipling, has neither the deep grounding in poetry nor the empathetic capability to illuminate Thomas's struggle to reconcile the polarities of his nature. Instead he gives us an exhaustively detailed, journalistic account of an incoherent life, leaving it to the reader to grope for a thread. His seeming objectivity extends to an extreme reluctance to either interpret significant information or give it its due emphasis; since no fact or anecdote seems more important than any other, vital points frequently sink into the surrounding bog of more trivial material.

As Lycett relentlessly catalogs Thomas's bad behavior -- his obsessive promiscuity, his chronic faithlessness to Caitlin, his epic bouts of drinking, his conscienceless extraction of "loans" from gullible admirers -- he forgets to show us what was worthwhile and heartrending about the man, what made him such a powerfully appealing figure. I suspect Lycett came to develop an unacknowledged distaste for his subject, only giving himself away near the end of this book with one contemptuous phrase describing the exhausted, sinking Thomas as "a sniveling wreck."

The great American poet Elizabeth Bishop had some memorable encounters with Thomas when he visited Washington in 1950, when she was poet in residence at the Library of Congress. A close friend of Robert Lowell's and Marianne Moore's and a woman who struggled with her own demons, she understood what it took to overcome tremendous self-doubt and write a dangerous kind of poetry: "just a straight conduit between birth & death . . . with not much space for living along the way." She recognized Thomas's "amazing gift for a kind of naked communication that makes a lot of poetry look like translation." To Pearl Kazin, one of the last women in Thomas's life, Bishop wrote: "I have met few people in my life I felt such an instantaneous sympathy and pity for, and although there must have been many things disastrously wrong, Dylan made most of our contemporaries seem small and disgustingly self-seeking and cautious and hypocritical and cold." It is a pity that this kind of balanced compassion and appreciation eluded Andrew Lycett, despite the reams of assiduously gathered research material he had to work from. *

Joyce Johnson's books include the just-published memoir "Missing Men," the 1983 National Book Critics Circle Award winner "Minor Characters" and the novel "In the Night Cafe."

Dylan Thomas at the White Horse Tavern, Greenwich Village